Plate type heat exchanger

ABSTRACT

In a plate type heat exchanger, a radius of curvature R1 of the protrusions formed in first plates is greater than a radius of curvature R2 of the depressions formed in the first plates to provide a plurality of asymmetrical flow paths.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims priority under 35 U.S.C. 119 and 35 U.S.C. 365 to Korean Patent Application No. 10-2019-0106683 (filed on Aug. 29, 2019), which is hereby incorporated by reference in its entirety.

BACKGROUND

The present disclosure relates to a plate type heat exchanger.

A heat exchanger is an apparatus for guiding heat exchange between at least two fluids and may include a plate type heat exchanger, for example. The plate type heat exchanger includes at least two flow paths, through which fluids having different temperatures flow. The at least two flow paths may be alternately arranged.

The plate type heat exchanger has higher heat exchange efficiency than the other heat exchanger and the size and weight thereof may be reduced in the structure thereof.

Japanese Patent Application Publication No. 11-270985 (Publication Date: Oct. 5, 1999) discloses a plate type heat exchanger.

In the plate type heat exchanger disclosed in the prior art, a heat exchange plate having two flow paths spaced apart from each other has an asymmetrical cross-sectional shape with respect to a central surface, such that one flow path has larger cross-sectional flow than the other flow path.

However, in the plate type heat exchanger disclosed in the prior art, since the heat exchanger is manufactured by stacking two types of plates, cost is high and a work process is complicated.

In addition, in the conventional plate type heat exchanger, since a difference in physical property or flow rate between two fluids flowing in two flow paths is not considered, in case of fluids having a large difference in physical property or flow rate, pressure loss occurs in any one fluid and heat exchange efficiency decreases.

SUMMARY

The present disclosure is devised to solve the above-described problems and an object of the present disclosure is to provide a plate type heat exchanger capable of improving heat exchange efficiency by minimizing pressure loss with respect to two fluids having different physical properties or flow rates.

Another object of the present disclosure is to provide a plate type heat exchanger capable of simplifying the work process of the heat exchanger and reducing cost.

Another object of the present disclosure is to provide a plate type heat exchanger capable of reducing the total number of stacks of a heat exchange plate, by optimizing the cross-sectional areas of flow paths, through which two fluids having different physical properties flow.

A plate type heat exchanger according to an embodiment of the present disclosure includes a plurality of first plates in which a plurality of protrusions protruding upward from a plate body and a plurality of depressions recessed downward from the plate body are alternately arranged, and a plurality of second plates having a shape symmetrical to that of the first plates in a vertical direction.

At this time, the plurality of first plates and the plurality of second plates are alternately stacked one by one in the vertical direction, the protrusions of the first plates are coupled to depressions of the second plates, and the depressions of the first plates are coupled to protrusions of the second plates, and

In particular, a radius of curvature R1 of the protrusions formed in the first plates may be greater than a radius of curvature R2 of the depressions formed in the first plates to provide a plurality of asymmetrical flow paths.

By such a configuration, a cross-sectional area of the flow paths formed by the protrusions of the first plates and the depressions of the second plates may be greater than that of the flow paths formed by the depressions of the first plates and the protrusions of the second plates.

In addition, water flows in the flow paths formed by the protrusions of the first plates and the depressions of the second plates, and refrigerant flows in the flow paths formed by the depressions of the first plates and the protrusions of the second plates, such that heat is exchanged. Therefore, it is possible to increase heat exchange efficiency between two fluids and minimize pressure loss.

For example, a cross-sectional area of the flow paths, through which the water flows, may be 1.1 times to 1.15 times that of the flow paths, through which the refrigerant flows.

In addition, the plurality of protrusions formed on the first plates may be spaced apart at a certain interval and may protrude at the same height, and the plurality of depressions formed in the first plates may be spaced apart at a certain interval and may be recessed at the same depth.

A plate type heat exchanger according to another embodiment of the present disclosure includes a plurality of first plates in which a plurality of protrusions protruding upward from a plate body, a plurality of depressions recessed downward from the plate body and inclined portions connecting the protrusions and the depressions are alternately arranged, and a plurality of second plates having a shape symmetrical to that of the first plates in a vertical direction.

At this time, the plurality of first plates and the plurality of second plates are alternately stacked one by one in the vertical direction, the protrusions of the first plates are coupled to depressions of the second plates, and the depressions of the first plates are coupled to protrusions of the second plates.

In particular, a width L1 of the protrusions formed in the first plates may be greater than a width L2 of the depressions formed in the first plates to provide a plurality of asymmetrical flow paths.

By such a configuration, a cross-sectional area of the flow paths formed by the protrusions of the first plates and the depressions of the second plates may be greater than that of the flow paths formed by the depressions of the first plates and the protrusions of the second plates.

In addition, water flows in the flow paths formed by the protrusions of the first plates and the depressions of the second plates, and refrigerant flows in the flow paths formed by the depressions of the first plates and the protrusions of the second plates, such that heat is exchanged. Therefore, it is possible to increase heat exchange efficiency between two fluids and minimize pressure loss.

For example, a cross-sectional area of the flow paths, through which the water flows, may be 1.1 times to 1.15 times that of the flow paths, through which the refrigerant flows.

In the present embodiment, the width L2 of the depressions formed in the first plates may be 0.3 times to 0.8 times the width L1 of the protrusions formed in the first plates. In addition, an angle between the inclined portions and the depressions may be in a range from 50 degrees to 80 degrees.

The inclined portions may include a first inclined portion inclined downward from one end of the protrusion to an end of an adjacent first depression, and a second inclined portion inclined downward from the other end of the protrusion to an end of an adjacent second depression.

At this time, the first inclined portion and the second inclined portion may have a bilateral symmetrical shape. For example, the first inclined portion, the protrusion and the second inclined portion may have an equilateral trapezoidal shape.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a plate type heat exchanger according to an embodiment of the present disclosure.

FIG. 2 is an exploded perspective view of a plate type heat exchanger according to an embodiment of the present disclosure.

FIG. 3 is a view illustrating a method of stacking heat exchange plates according to an embodiment of the present disclosure.

FIG. 4 is a cross-sectional view showing a portion of a heat exchange plate according to an embodiment of the present disclosure.

FIG. 5 is a view enlarging the cross-section of the heat exchange plate of FIG. 4.

FIG. 6 is a cross-sectional view schematically showing a portion of a heat exchange plate according to another embodiment of the present disclosure.

FIG. 7 is a graph showing change in calorific value according to a ratio between flow path cross-sectional areas of water and refrigerant according to an embodiment of the present disclosure.

FIG. 8 is a graph showing pressure loss according to a ratio between flow path cross-sectional areas of water and refrigerant according to an embodiment of the present disclosure.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings.

In the following detailed description of the preferred embodiments, reference is made to the accompanying drawings that form a part hereof, and in which is shown by way of illustration specific preferred embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is understood that other embodiments may be utilized and that logical structural, mechanical, electrical, and chemical changes may be made without departing from the spirit or scope of the invention. To avoid detail not necessary to enable those skilled in the art to practice the invention, the description may omit certain information known to those skilled in the art. The following detailed description is, therefore, not to be taken in a limiting sense.

Also, in the description of embodiments, terms such as first, second, A, B, (a), (b) or the like may be used herein when describing components of the present invention. Each of these terminologies is not used to define an essence, order or sequence of a corresponding component but used merely to distinguish the corresponding component from other component(s). It should be noted that if it is described in the specification that one component is “connected,” “coupled” or “joined” to another component, the former may be directly “connected,” “coupled,” and “joined” to the latter or “connected”, “coupled”, and “joined” to the latter via another component.

FIG. 1 is a perspective view of a plate type heat exchanger according to an embodiment of the present disclosure. FIG. 2 is an exploded perspective view of a plate type heat exchanger according to an embodiment of the present disclosure. FIG. 3 is a view illustrating a method of stacking heat exchange plates according to an embodiment of the present disclosure.

Referring to FIGS. 1 to 3, the plate type heat exchanger 1 according to the embodiment of the present disclosure includes a plate package P including a plurality of heat exchange plates 30 and 40 and two end plates 10 and 20 provided at both ends of the plate package P. For example, the heat exchange plates 30 and 40 and the two end plates 10 and 20 may have a quadrangular panel shape.

The heat exchange plates 30 and 40 may be composed of a metal material having excellent thermal conductivity and excellent pressure resistance. For example, the heat exchange plates 30 and 40 may be composed of a stainless material.

The heat exchange plates 30 and 40 includes a plurality of first plates 30 and a plurality of second plates 40. The first plates 30 and the second plates 40 may be alternately stacked one by one in a vertical direction based on FIG. 1.

The vertical direction may be referred to as a “stacking direction”.

Flow paths, through which fluid flows, are formed between the plurality of heat exchange plates 30 and 40. The flow paths include a first flow path (see 41 of FIG. 4), through which first fluid flows, and a second flow path (see 43 of FIG. 4), through which second fluid flows. The first and second flow paths 41 and 43 may be alternately arranged in turn. The first and second flow paths 41 and 43 may be alternately formed in the stacking direction, such that the first fluid and the second fluid independently flow without being combined.

Refrigerant may flow in the first flow path 41. The first flow path 41 is a flow path, through which refrigerant flows, and thus may be referred to as a “refrigerant flow path”. Water may flow in the second flow path 43. The second flow path 43 is a flow path, through which water flows, and thus may be referred to as a “water flow path”.

The two end plates 10 and 20 include a first end plate 10 provided above the plate package P and a second end plate 20 provided below the plate package P. That is, the plate package P may be disposed between the two end plates 10 and 20.

The plate type heat exchanger 1 further includes sockets 61, 65, 71 and 75 for providing the first fluid and the second fluid into the plate package P or discharging the first fluid and the second fluid from the plate package P to the outside.

The sockets 61, 65, 71 and 75 may include at least one of a first inlet 61, a second inlet 71, a first outlet 65 or a second outlet 75.

Specifically, the plate type heat exchanger 1 further includes the first inlet 61, through which the first fluid flows into the plate package P, and the second inlet 71, through which the second fluid flows into the plate package P.

The first inlet 61 and the second inlet 71 may be coupled to the first end plate 10. The first and second fluids have a temperature difference and may exchange heat with each other. For example, the first fluid may be refrigerant and the second fluid may be water. Accordingly, the first inlet 61 may be referred to as a “refrigerant inlet” and the second inlet 71 may be referred to as a “water inlet”.

The plate type heat exchanger 1 further includes a first outlet 65, through which the first fluid is discharged from the plate package P, and a second outlet 75, through which the second fluid is discharged from the plate package P. The first outlet 65 and the second outlet 75 may be coupled to the first end plate 10.

For example, the first inlet 61 and the second inlet 71 may be disposed at corners located in a diagonal direction among the four corners of the first end plate 10. The first outlet 65 and the second outlet 75 may be disposed at corners located in another diagonal direction among the four corners of the first end plate 10. That is, the first inlet 61 and the second outlet 75 may be adjacently disposed, and the second inlet 71 and the second outlet 65 may be adjacently disposed.

Alternatively, the first inlet 61 and the first outlet 65 may be disposed at corners located in a diagonal direction among the four corners of the first end plate 10, and the second inlet 71 and the second outlet 75 may be disposed at corners located in another diagonal direction among the four corners of the first end plate 10.

The heat exchange plates 30 and 40 include the plurality of first plates 30 and the plurality of second plates 40. the first plates 30 and the second plates 40 may have the same shape. Alternatively, the first plates 30 and the second plates 40 may have a symmetrical shape.

In the present embodiment, the first plate 30 includes a plate body 31 having a substantially quadrangular panel shape and an edge portion 32 surrounding the outside of the plate body 31.

In addition, the first plate 30 further includes a plurality of input/output ports 33, 34, 35 and 36 disposed at four corners of the plate body 31 to communicate with the first and second inlets 61 and 71 and the first and second outlets 65 and 75 to guide flow of the fluid. The plurality of input/output ports 33, 34, 35 and 36 may penetrate through at least a portion of the plate body 31.

The plurality of input/output ports 33, 34, 35 and 36 includes a first input port 33 formed at a position corresponding to the first inlet 61 such that the first fluid (refrigerant) is introduced therethrough, and a first output port 34 formed at a position corresponding to the first outlet 65 such that the first fluid is discharged therethrough.

The first input port 33 may be referred to as a “refrigerant input port” and the first output port 34 may be referred to as a “refrigerant output port”.

The refrigerant may flow into the first flow path 41 of the plate package P while flowing the lower side of the first plates 30 through the first input port 33, and the refrigerant heat-exchanged in the first flow path 41 may be discharged from the plate package P through the first output port 34 to flow upward toward the first outlet 65.

The plurality of input/output ports 33, 34, 35 and 36 includes a second input port 35 formed at a position corresponding to the second inlet 71 such that the second fluid (water) is introduced therethrough and a second output port 36 formed at a position corresponding to the second outlet 75 such that the second fluid is discharged therethrough.

The second input port 35 may be referred to as a “water input port”, and the second output port 36 may be referred to as a “water output port”.

Water may flow into the first flow path 43 of the plate package P while flowing to the lower side of the first plates 30 through the second input port 35, and the water heat-exchanged in the first flow path 43 may be discharged from the plate package P through the second output port 36 to flow upward toward the second outlet 75.

The plurality of input/output ports 33, 34, 35 and 36 is formed in the first plates 30 and may be referred to as a “first port”.

In addition, the plurality of input/output ports may be formed even in the second plates 40. Accordingly, the plurality of input/output ports formed in the second plates 40 may be referred to as a “second port”.

The outer surface of the plate body 31 includes irregularities. Specifically, the irregularities include protrusions 37 protruding upward from the upper surface of the plate body 31 and depressions 38 recessed downward from the upper surface of the plate body 31.

A plurality of protrusions 37 and depressions 38 may be provided and may be alternately arranged. In addition, irregularities may be included in the lower surface of the plate body 31.

For example, by the plurality of protrusions 37 and the plurality of depressions 38, a herringbone pattern may be formed in the upper and lower surfaces of the plate body 31.

The irregularities of the plate body 31 may be provided to be in contact with irregularities provided in another adjacent heat exchange plate 40. In addition, the contacted irregularities may be adhered by a predetermined method. The predetermined method may include welding or adhesion using an adhesive. For example, the protrusions of the second plates 40 may be adhered to the depressions 38 of the first plates 30.

The adjacent plates forming the first and second flow paths 41 and 43 may be alternately arranged. For example, the first and second plate are adhered to form the first flow path 41 and the second and third plates are adhered to form the second flow path 43. In addition, the third and fourth plates may be adhered to form the first flow path 41. This arrangement may be repeated to configure the plate package P.

The plate type heat exchanger 1 further includes a plurality of cooper plates 50 for brazing the plurality of plates 10, 20, 30 and 40 configuring the plate type heat exchanger 1.

The plurality of cooper plates 50 may be inserted between the first end plate 10 and the first plate 30, between the first plate 30 and the second plate 40 and between the second plate 40 and the second end plate 20 and then brazed. That is, the cooper plates 50 may be used as filler metal for brazing.

In the present embodiment, the cooper plate 50 may be disposed between the first end plate 10 and the first plate 30, the cooper plate 50 may be disposed between the first plate 30 and the second plate 40, and the cooper plate 50 may be disposed between the second plate 40 and the second end plate 20.

The cooper plate 50 has a flat surface and may be brazed by sequentially stacking the heat exchange plates 30 and 40 in which the first and second flow paths 41 and 43 having a V shape (wrinkled shape) are formed. At this time, the cooper plate 50 is filler metal and the cooper plate 50 is melted at a high temperature by a capillary phenomenon between the stacked heat exchange plates 30 and 40 to be adhered to the heat exchange plates 30 and 40 by a cooling process.

The cooper plate 50 includes a cooper body 51 forming the flat surface and an edge portion 52 surrounding the outside of the cooper body 51. The edge portion 52 extend downward from the edge of the cooper body 51.

The cooper body 51 includes a first hole 53 formed at a position corresponding to the first inlet 61, a second hole 54 formed at a position corresponding to the first outlet 65, a third hole 55 formed at a position corresponding to the second inlet 71 and a fourth hole 56 formed at a position corresponding to the second outlet 75.

The first end plate 10 is disposed above the plate package P, and is coupled with the first and second inlets 61 and 71 and the first and second outlets 65 and 75.

The first end plate 10 includes a base 11 having a flat surface and an edge portion 12 extending from the edge of the base 11. The edge portion 12 may extend downward from the edge of the base 11.

The base 11 includes a first insertion hole 12, into which the first inlet 61 is inserted, a second insertion hole 14, into which the first outlet 65 is inserted, a third insertion hole 15, into which the second inlet 71 is inserted, and a fourth insertion hole 16, into which the second outlet 75 is inserted.

The first to fourth insertion holes 13, 14, 15 and 16 are holes, into which sockets are inserted, and thus may be referred to as “socket holes”.

The first insertion hole 13 is aligned in the vertical direction (overlapping direction) with the first hole 53 of the cooper plate 50 and the first input port 33 of the heat exchange plate, and the second insertion hole 14 is aligned in the vertical direction with the second hole 54 of the cooper hole 50 and the first output port 34 of the heat exchange plate 30.

The third insertion hole 15 is aligned in the vertical direction with the third hole 55 of the copper plate 50 and the second input port 35 of the heat exchange plate 30, and the fourth insertion hole 16 is aligned in the vertical direction with the fourth hole 56 of the cooper plate 50 and the second output port 36 of the heat exchange plate 30.

Accordingly, refrigerant flows into the plate package P through the first inlet 61 and flows along the first flow path 41, thereby being discharged through the first outlet 65. Water flows into the plate package P through the second inlet 71 and flows along the first flow path 43, thereby being discharged through the second outlet 75.

In this process, the refrigerant of the first flow path 41 may exchange heat with the water of the second flow path 43. Since the first flow path 41 and the second flow path 43 are alternately arranged in the stacking direction, the refrigerant and the water may independently flow without being mixed.

FIG. 4 is a cross-sectional view showing a portion of a heat exchange plate according to an embodiment of the present disclosure. FIG. 5 is a view enlarging the cross-section of the heat exchange plate of FIG. 4.

Referring to FIGS. 4 and 5, as described above, the first flow path 41, through which the first fluid flows, and the second flow path 43, through which the second fluid flows, are formed between the plurality of heat exchange plates 30 and 40.

Specifically, each the plurality of first plates 30 includes the plurality of protrusions 37 protruding upward from the plate body and the plurality of depressions 38 recessed downward from the plate body. The plurality of protrusions 37 and depressions 38 may be provided in a herringbone pattern.

Each the plurality of second plates 40 includes the plurality of protrusions 47 protruding upward from the plate body and the plurality of depressions 48 recessed downward from the plate body. The plurality of protrusions 47 and depressions 48 may be provided in a herringbone pattern.

The first plates 30 has a sine-wave cross-sectional shape. That is, the first plates 30 may have a sine-wave or wave-shaped longitudinal cross section.

At this time, the first plate 30 may have an asynchronous sine-wave cross-sectional shape due to a difference between curvature radii R1 and R2 of the protrusion 47 and the depression 48.

The second plates 40 may have a sine-wave or wave-shaped longitudinal cross section similarly to the first plates 30.

However, the second plates 40 may have a cross-sectional shape of a sine wave which is symmetrical to the sine wave of the first plates 30.

Specifically, the plurality of first plates 30 and the plurality of second plates 40 may be stacked and fixed one by one in the vertical direction. At this time, each protrusion 37 of the first plate 30 may be in contact with and fixed to the adjacent second plate 40, that is, the depression 48 of the second plate 40 located above the first plate 30.

In addition, each depression 38 of the first plate 30 may be in contact with and fixed to the adjacent second plate 40, that is, the protrusion 47 of the second plate 40 located below the first plate 30.

Accordingly, the second plate 40 may have a shape symmetrical to the first plate 30 in the vertical direction or may be disposed to be symmetrical to the first plate 30 in the vertical direction.

In addition, since the first plate 30 and the second plate 40 are disposed to be symmetrical with each other, the first plate 30 and the second plates 40 may be substantially manufactured in the same shape.

That is, a plurality of partitioned flow paths may be provided by manufacturing a plurality of plates having one type of shape and then placing the plates to be vertically symmetrical with each other one by one. According to such a configuration, since the heat exchange plate may be manufactured by stacking plates of one type without using a method of stacking plates of two types, the work process is simple and costs are reduced.

Meanwhile, the heat exchange plates 30 and 40 form flow paths 41 and 43 having different cross-sectional areas.

Specifically, when the plurality of first plates 30 and the plurality of second plates 40 are alternately arranged, the first flow path 41 and the second flow path 43 are provided. At this time, the cross-sectional areas of the first flow path 41 and the second flow path are different.

In the present embodiment, the cross-sectional area of the second flow path 42 is greater than that of the first flow path 41. For example, the cross-sectional area of the second flow path 42 may be 1.1 times to 1.15 times that of the first flow path 41.

The reason why the cross-sectional areas of the first flow path 41 and the second flow path 43 are different is because a difference in flow rate between two fluids requiring heat exchange in a system operating condition may be large.

If the difference in flow rate between two fluids requiring heat exchange is relatively large, when the two fluid flows in the flow paths having the same cross-sectional area, a difference in reynold's number may increase according to the physical properties (e.g., viscosity, specific volume, etc.) and the flow rate of each fluid. In this case, heat transfer may be inefficient. Accordingly, the cross-sectional area of the flow path, through which each fluid flows, needs to be appropriately designed according to the physical properties and flow rate of each fluid.

In the present embodiment, refrigerant may flow in the first flow path 41 and water may flow in the second flow path 43. At this time, since refrigerant and water have different physical properties and/or flow rates, when the refrigerant and water exchange heat while flowing in the flow paths having the same cross-sectional area, pressure loss may occur. When pressure loss occurs, the flow rate may decrease and thus heat exchange performance may be reduced.

However, in the present disclosure, since the cross-sectional area of the first flow path 41, through which the refrigerant flows, is designed to be less than that of the second flow path 43, through which water flows, it is possible to minimize pressure loss and improve heat exchange performance.

To this end, in the first plate 30, the plurality of protrusions 37 and the plurality of depressions 38 are disposed to be spaced apart at a certain interval.

Specifically, the plurality of protrusions 37 is formed to be spaced apart at a certain interval and is provided at the same height. In other words, the peaks 37 a of the plurality of protrusions 37 may have the same height and a distance L1 between the peaks 37 a of two adjacent protrusions 37 may be kept constant.

In addition, the plurality of depressions 38 is formed to be spaced apart at a certain interval and is provided at the same depth. In other words, the lowest points 38 a of the plurality of depressions 38 may have the same depth and a distance between the lowest points 38 a of two adjacent depressions 38 may be kept constant.

Meanwhile, in the present embodiment, the “protrusion” may mean a portion (curved surface) corresponding to the upper portion of a line bisecting the first plate 30 or the second plate 40 in the vertical direction, and the “depression” may mean a portion (curved surface) corresponding to the lower portion of the line bisecting the first plate 30 or the second plate 40 in the vertical direction.

That is, the plurality of protrusions 37 and the plurality of depressions 38 may be alternately connected based on the cross-sectional shape of the first plates 30, thereby forming a sine wave.

However, the radius of curvature R1 of the protrusion 37 is greater than the radius curvature R2 of the depression 38. In other words, a curved portion corresponding to the protrusion 37 may be relatively larger than a curved portion corresponding to the depression 38.

By such a configuration, when the first plate 30 and the second plate 40 are coupled, by contact between the protrusions 37 and depressions 38 of the first plate 30 and the protrusions 48 and depressions 47 of the second plate 40, two flow paths 41 and 43 having different cross-sectional areas are formed.

The protrusion 37 of the first plate 30 is in contact with and fixed to the depression 48 of the second plate 40 and the depression 38 of the first plate 30 is in contact with and fixed to the protrusion 47 of the second plate 40, such that the first flow path 41 and the second flow path 43 which are asymmetrical flow paths are alternately formed.

FIG. 6 is a cross-sectional view schematically showing a portion of a heat exchange plate according to another embodiment of the present disclosure.

Referring to FIG. 6, the heat exchange plates 30 and 40 according to another embodiment of the present disclosure may have a trapezoidal cross-section.

Specifically, each of the plurality of first plates 30 includes the plurality of protrusions 37 protruding upward from the plate body and the plurality of depressions 38 recessed downward from the plate body. The plurality of protrusions 37 and depressions 38 may be provided in a herringbone pattern.

Each of the plurality of second plates 40 includes the plurality of protrusions 47 protruding upward from the plate body and the plurality of depressions 48 recessed downward from the plate body. The plurality of protrusions 47 and depressions 48 may be provided in a herringbone pattern.

The first plates 30 may have a trapezoidal or zigzag cross-sectional shape. The second plates 40 may have a trapezoidal or zigzag cross-sectional shape.

However, the second plates 40 may have a cross-sectional shape which is vertically symmetrical to that of the first plates 30.

Specifically, the plurality of first plates 30 and the plurality of second plates 40 may be stacked and fixed one by one in the vertical direction. At this time, each protrusion 37 of the first plate 30 may be in contact with and fixed to the adjacent the second plate 40, that is, the depression 48 of the second plate 40 located above the first plate 30.

In addition, each depression 38 of the first plate 30 may be in contact with and fixed to the adjacent second plate 40, that is, the protrusion 47 of the second plate 40 located below the first plates 30.

Accordingly, the second plate 40 may have a shape symmetrical to that of the first plate 30 in the vertical direction or may be disposed to be symmetrical to the first plates 30 in the vertical direction.

In addition, since the first plate 30 and the second plate 40 are disposed to be symmetrical to each other, the first plate 30 and the second plate 40 may be substantially manufactured in the same shape.

The first plate 30 further includes an inclined portion 39 connecting the protrusion 37 and the depression 38.

Specifically, the inclined portion 39 may be inclined downward from both ends of the protrusion 37 to be connected to the depression 38.

For example, as shown in FIG. 6, the inclined portion 39 may include a first inclined portion 39 a inclined downward from the right end of the protrusion 37 to an adjacent depression 38 and a second inclined portion 39 b inclined downward from the left end of the protrusion 37 to an adjacent depression 38.

That is, the inclined portion 39 may be understood as a portion connecting the protrusion 37 and the depressions 38 adjacent to the protrusion 37. Based on FIG. 6, the second inclined portion 39 b, the protrusion 37, the first inclined portion 39 a and the depression 38 are sequentially and continuously disposed, thereby forming the cross-sectional shape of the first plate 30.

At this time, the first inclined portion 39 a and the second inclined portion 39 b may have a bilateral symmetrical shape. Therefore, the length and inclination of the first inclined portion 39 a is the same as or correspond to those of the inclined portion 39 b, and the first plate 30 may have an equilateral trapezoidal cross section.

The second plate 40 further includes an inclined portion 49 connecting the protrusion 47 and the depression 48.

Specifically, the inclined portion 49 may be inclined downward from both ends of the protrusion 47 to be connected to the depression 48.

For example, as shown in FIG. 6, the inclined portion 49 may include a first inclined portion 49 a inclined downward from the right end of the protrusion 47 to an adjacent depression 48 and a second inclined portion 49 b inclined downward from the left end of the protrusion 47 to an adjacent depression 48.

That is, the inclined portion 49 may be understood as a portion connecting the protrusion 47 and the depressions 48 adjacent to the protrusion 47. Based on FIG. 6, the second inclined portion 49 b, the protrusion 47, the first inclined portion 39 a and the depression 48 may be sequentially and continuously disposed, thereby shaping the cross-sectional shape of the second plate 30.

At this time, the first inclined portion 49 a and the second inclined portion 49 b may have a bilateral symmetrical shape. Therefore, the length and inclination of the first inclined portion 49 a is the same as or correspond to those of the inclined portion 49 b, and the second plate 40 may have an equilateral trapezoidal cross section.

Meanwhile, the plurality of protrusions 37 of the first plate 30 are formed to be spaced apart at a certain interval and is provided at the same height. At this time, the protrusion 37 has a certain width L1 or a straight line section. For example, the plurality of protrusions 37 is formed to have the same height H2 and width L1 and is spaced apart from each other.

The plurality of depressions 38 of the first plate 30 is formed to be spaced apart at a certain interval and is provided at the same depth. At this time, the depression 38 has a certain width L2 or a straight line section. For example, the plurality of depressions 38 is formed to have the same height H2 and width L2 and is spaced apart from each other.

At this time, the width L2 of the depression 38 is less than the width L1 of the protrusion 37. This is because the first plate 30 and the second plate 40 are alternately arranged to form flow paths having different cross-sectional areas.

In particular, in the present embodiment, the width L2 of the depression 38 is 0.3 to 0.8 times the width L1 of the protrusion 37. When the width L2 of the depression 38 is less than 0.3 times the width L1 of the protrusion 37, the width of the flow path is reduced, thereby causing pressure loss. As a result, heat exchange efficiency may be reduced.

Accordingly, the width L2 of the depression 38 is equal to or greater than 0.3 times the width L1 of the protrusion 37.

In addition, in the present embodiment, the inclination of the inclined portion 39, that is, the angle between the protrusion 37 or the depression 38 and the inclined portion 39, needs to be appropriately designed.

For example, when the inclination of the inclined portion 39 is two small, resistance is generated while fluid flows and thus heat exchange efficiency may be reduced. In addition, since the number of stacks of the heat exchange plate for configuring the plate package P increases, product costs increase.

Accordingly, in the present embodiment, the angle between the protrusion 37 or the depression 38 and the inclined portion 39 may be designed to be 50 degrees to 80 degrees.

FIG. 7 is a graph showing change in calorific value according to a ratio between flow path cross-sectional areas of water and refrigerant according to an embodiment of the present disclosure.

Referring to FIG. 7, the horizontal axis of the graph represents the ratio between the flow path cross-sectional areas of water and refrigerant of the graph. For example, the ratio between the flow path cross-sectional areas of water and refrigerant of 100% means that the ratio of the flow path cross-sectional area of water to the flow path cross-sectional area of refrigerant is 1:1. That is, the ratio between the flow path cross-sectional areas of water and refrigerant of 100% means that the cross-sectional areas of the flow path, through which water passes, and the flow path, through which refrigerant passes, are the same.

As another example, the ratio between the flow path cross-sectional areas of water and refrigerant of 105% means that the ratio of the flow path cross-sectional area of water to the flow path cross-sectional area of refrigerant is 105:100. That is, this means that the cross-sectional area of the flow path, through which water passes, is greater than the flow path, through which refrigerant passes, by 5%.

The vertical axis of the graph represents change in calorific value (kW) occurring when heat is exchanged while water and refrigerant respectively pass through the water flow path and the refrigerant flow path. The larger change in calorific value, the better heat exchange efficiency between water and refrigerant. The smaller change in calorific value, the worse heat exchange efficiency between water and refrigerant.

Referring to the graph of FIG. 7, it can be seen that, as the ratio between the flow path cross-sectional areas of water and refrigerant increases, heat exchange efficiency between water and refrigerant increases. That is, when the ratio between the flow path cross-sectional areas of water and refrigerant is 100%, change in calorific value is 8.4 kW. In contrast, when the ratio between the flow path cross-sectional areas of water and refrigerant exceeds 110%, change in calorific value is 9.2 kW.

However, it can be seen that, when the ratio between the flow path cross-sectional areas of water and refrigerant exceeds 110%, there is no significant change in calorific value.

Accordingly, in the present disclosure, by designing the ratio between the flow path cross-sectional areas of water and refrigerant to exceed 110%, it is possible to maximize heat exchange efficiency between water and refrigerant.

FIG. 8 is a graph showing pressure loss according to a ratio between flow path cross-sectional areas of water and refrigerant according to an embodiment of the present disclosure.

Referring to FIG. 8, the horizontal axis of the graph represents the ratio between the flow path cross-sectional areas of water and refrigerant of the graph. For example, the ratio between the flow path cross-sectional areas of water and refrigerant of 100% means that the ratio of the flow path cross-sectional area of water to the flow path cross-sectional area of refrigerant is 1:1. That is, the ratio between the flow path cross-sectional areas of water and refrigerant of 100% means that the cross-sectional areas of the flow path, through which water passes, and the flow path, through which refrigerant passes, are the same.

As another example, the ratio between the flow path cross-sectional areas of water and refrigerant of 105% means that the ratio of the flow path cross-sectional area of water to the flow path cross-sectional area of refrigerant is 105:100. That is, this means that the cross-sectional area of the flow path, through which water passes, is greater than the flow path, through which refrigerant passes, by 5%.

The vertical axis of the graph represents pressure loss (kPa) occurring while water and refrigerant respectively pass through the water flow path and the refrigerant flow path.

Here, pressure loss includes pressure loss which may occur when fluid hits a flow path pipe while fluid passes through the flow path pipe. The amount of pressure loss may vary not only according to the inner diameter and cross-sectional area of the flow path pipe but also the physical properties (e.g., viscosity, specific volume, etc.) of the fluid. When a large amount of pressure loss occurs in the flow path pipe, through which fluid flows, the pressure of flowing fluid decreases and thus heat exchange efficiency between fluids may decrease.

Referring to the graph of FIG. 8, it can be seen that, as the ratio between the flow path cross-sectional areas of water and refrigerant increases, pressure loss of the water flow path decreases. This is because, as the cross-sectional area of the flow path, through which water passes, increases, resistance generated when water passes through the water pipe decreases.

In contrast, it can be seen that, as the ratio between the flow path cross-sectional areas of water and refrigerant increases, pressure loss of the refrigerant flow path increases. This is because, when the cross-sectional area of the refrigerant flow path is relatively less than that of the water flow path, resistance generated when refrigerant passes through a refrigerant pipe increases.

Accordingly, the ratio between the flow path cross-sectional areas of water and refrigerant needs to be appropriately designed and, in particular, both the pressure loss of water and the pressure loss of refrigerant need to be considered.

Meanwhile, in the graph of FIG. 8, it can be seen that the pressure loss of the water flow path is rapidly reduced in a section in which the ratio between the flow path cross-sectional areas of water and refrigerant is 110%. In addition, it can be seen that, after a section in which the ratio between the flow path cross-sectional areas of water and refrigerant is 115%, a difference in pressure loss of the water flow path is reduced.

Accordingly, in the present disclosure, the cross-sectional area of the water flow path is 1.1 times to 1.15 times that of the refrigerant flow path, in consideration of the section in which the pressure loss of the water flow path is rapidly reduced and the difference in pressure loss of the water flow path is reduced. Therefore, it is possible to improve heat exchange efficiency between water and refrigerant and to minimize pressure loss of the water flow path and the refrigerant flow path. 

What is claimed is:
 1. A plate type heat exchanger comprising: a plate package in which a plurality of heat exchange plates is stacked to form a flow path, through which fluid flows; an end plate coupled to an outside of the plate package; and a socket connected to the plate package by passing through the end plate, wherein the plurality of heat exchange plates includes: a plurality of first plates in which a plurality of protrusions protruding upward from a plate body and a plurality of depressions recessed downward from the plate body are alternately arranged; and a plurality of second plates having a shape symmetrical to that of the first plates in a vertical direction, wherein the plurality of first plates and the plurality of second plates are alternately stacked one by one in the vertical direction, wherein the protrusions of the first plates are coupled to depressions of the second plates, wherein the depressions of the first plates are coupled to protrusions of the second plates, and wherein a radius of curvature R1 of the protrusions formed in the first plates is greater than a radius of curvature R2 of the depressions formed in the first plates to provide a plurality of asymmetrical flow paths.
 2. The plate type heat exchanger of claim 1, wherein a cross-sectional area of the flow paths formed by the protrusions of the first plates and the depressions of the second plates is greater than that of the flow paths formed by the depressions of the first plates and the protrusions of the second plates.
 3. The plate type heat exchanger of claim 1, wherein water flows in the flow paths formed by the protrusions of the first plates and the depressions of the second plates, and wherein refrigerant flows in the flow paths formed by the depressions of the first plates and the protrusions of the second plates, such that heat is exchanged.
 4. The plate type heat exchanger of claim 3, wherein a cross-sectional area of the flow paths, through which the water flows, is 1.1 times to 1.15 times that of the flow paths, through which the refrigerant flows.
 5. The plate type heat exchanger of claim 1, wherein the plurality of protrusions formed on the first plates are spaced apart at a certain interval and protrude at the same height.
 6. The plate type heat exchanger of claim 1, wherein the plurality of depressions formed in the first plates are spaced apart at a certain interval and are recessed at the same depth.
 7. A plate type heat exchanger comprising: a plate package in which a plurality of heat exchange plates is stacked to form a flow path, through which fluid flows; an end plate coupled to an outside of the plate package; and a socket connected to the plate package by passing through the end plate, wherein the plurality of heat exchange plates includes: a plurality of first plates in which a plurality of protrusions protruding upward from a plate body, a plurality of depressions recessed downward from the plate body and inclined portions connecting the protrusions and the depressions are alternately arranged; and a plurality of second plates having a shape symmetrical to that of the first plates in a vertical direction, wherein the plurality of first plates and the plurality of second plates are alternately stacked one by one in the vertical direction, wherein the protrusions of the first plates are coupled to depressions of the second plates, wherein the depressions of the first plates are coupled to protrusions of the second plates, and wherein a width L1 of the protrusions formed in the first plates is greater than a width L2 of the depressions formed in the first plates to provide a plurality of asymmetrical flow paths.
 8. The plate type heat exchanger of claim 7, wherein a cross-sectional area of the flow paths formed by the protrusions of the first plates and the depressions of the second plates is greater than that of the flow paths formed by the depressions of the first plates and the protrusions of the second plates.
 9. The plate type heat exchanger of claim 7, wherein water flows in the flow paths formed by the protrusions of the first plates and the depressions of the second plates, and wherein refrigerant flows in the flow paths formed by the depressions of the first plates and the protrusions of the second plates, such that heat is exchanged.
 10. The plate type heat exchanger of claim 9, wherein a cross-sectional area of the flow paths, through which the water flows, is 1.1 times to 1.15 times that of the flow paths, through which the refrigerant flows.
 11. The plate type heat exchanger of claim 7, wherein the width L2 of the depressions formed in the first plates is 0.3 times to 0.8 times the width L1 of the protrusions formed in the first plates.
 12. The plate type heat exchanger of claim 7, wherein an angle between the inclined portions and the depressions is in a range from 50 degrees to 80 degrees.
 13. The plate type heat exchanger of claim 7, wherein the inclined portions include: a first inclined portion inclined downward from one end of the protrusion to an end of an adjacent first depression; and a second inclined portion inclined downward from the other end of the protrusion to an end of an adjacent second depression.
 14. The plate type heat exchanger of claim 13, wherein the first inclined portion and the second inclined portion have a bilateral symmetrical shape.
 15. The plate type heat exchanger of claim 13, wherein the first inclined portion, the protrusion and the second inclined portion have an equilateral trapezoidal shape.
 16. The plate type heat exchanger of claim 7, wherein the plurality of protrusions formed on the first plates are spaced apart at a certain interval and protrude at the same height.
 17. The plate type heat exchanger of claim 7, wherein the plurality of depressions formed in the first plates are spaced apart at a certain interval and are recessed at the same depth. 